I used SPD s at first crank brothers egg beaters. They are easier to get into the pedal compared to the SHimano SPD-SL s I now use. The difference is for me I like the power transfer and the bigger platform of the Shimano 3 bolt shoes. I don't like much float either and prefer the pedal to be solidly engaged. The only advantage to SPD pedals was the 4 sided entry made things faster and easier, also they were better for walking around.
The negative is that the Crank Brothers eggbeaters would only last about a year and the bearings go bad. They can be replaced but about as easy to buy a new set of pedals for just a few bucks more. The Shimano 105's I now have much better they have been going strong at least 4 years zero maintenance. The pedals work great and I do wear out cleats about every 2 years. The pedals themselves just keep running for sure. I do at times even now get a bit slow clipping in if things are busy but in the end I like the solid feeling much better. If I was only riding around town or lots of stops maybe SPDs, but then probably better to simply have open pedals if stopping all the time at intersections.